Was outside watering a couple plants and noticed a stinkin’ mud dauber going into my 400A ATS through the N3R drain hole . “Oh no you di-int!” Pulled the cover and dead-front to find six nests…..thankfully not on anything too important only the ground lug etc…. Grabbed my Cementex tool set and got everything knocked off and cleaned up. Also put a little piece of steel wool in the hole which will hopefully let it drain and keep the little flying bastards out of the panel. Sure glad I found out what was going on before something happened that would cause me to say bad words.